Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 159 · 40 questions

Remember (Find the topic, use the idea): Find the topic: circuit, safety, formula, component, program, sensor or IoT. Use that lesson’s rule — complete loop, V = I × R, P = V × I, last command wins, true → if part. Safety answers are always: low voltage, dry hands, an adult, never the mains.

1. 1.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the widest gap (c) any band (d) the gold band
2. 2.🔘 A cell, a bulb and switches A, B, C and D are joined one after another in a single loop (series). A is OFF, B is ON, C is OFF and D is OFF. Does the bulb glow? (a) No (b) Yes
3. 3.🧮 Resistors of 50 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
4. 4.⚠️ Is it safe to build with an adult near? (a) safe (b) not safe
5. 5.🔋 What is a battery? (a) two or more cells joined (b) one single wire (c) a switch with a lid (d) a kind of bulb
6. 6.🔢 To get a sensor reading onto a phone, which comes first: “the sensor measures” or “the app shows it”? (a) the app shows it (b) the sensor measures
7. 7.🧮 A 5 V battery is joined to 3 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
8. 8.🤖 if (temperature > 35) { show “Hot” } else if (temperature > 21) { show “Warm” } else { show “Cool” }
   The temperature is 38 °C. What is shown? (a) Warm (b) Cool (c) Hot
9. 9.True or false: “own switch for each bulb” is true of a series circuit. (a) True (b) False
10. 10.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a wooden stick. Does the bulb glow? (a) No (b) Yes
11. 11.🔍 Which is the odd one out? (a) a speaker (b) a light sensor (c) a turning knob (d) a keypad
12. 12.🔺 A current of 20 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
13. 13.🔍 Which is the odd one out? (a) take cells out after use (b) touch a switch when wet (c) throw cells in a fire (d) fly a kite near wires
14. 14.🔺 A current of 10 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
15. 15.💡 2 identical bulbs are joined in parallel (each on its own side-by-side path) with a battery and a closed switch on the main wire. Bulb 1 is taken out of its holder. How many bulbs glow?
16. 16.⏱️ What does “wait 500 ms” do? (a) waits 500 seconds (b) blinks 500 times (c) pauses for half a second (d) turns the LED off
17. 17.True or false: to read app permissions is a risky habit. (a) False (b) True
18. 18.🔐 Privacy for a smart device means controlling … (a) its colour (b) how loud it beeps (c) its battery size (d) who can see your data
19. 19.Which of these saves electricity? (a) leave fridge door open (b) run fans in empty rooms (c) use old filament bulbs (d) close the fridge quickly
20. 20.🤖 if (distance < 10) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 8 cm. What happens? (a) buzzer beeps (b) buzzer is silent
21. 21.Which of these is true of a parallel circuit? (a) a single current path (b) many paths for current (c) bulbs share the voltage (d) one bulb out, all go out
22. 22.True or false: to spot someone walking in, use a motion sensor. (a) False (b) True
23. 23.🧩 Which part changes electrical energy into movement? (a) a resistor (b) a motor (c) a fuse (d) an LED
24. 24.True or false: to use old filament bulbs saves electricity. (a) True (b) False
25. 25.⚠️ What protects home wiring by melting or tripping when too much current flows? (a) a bulb (b) a plug top (c) a fuse or MCB (d) a long wire
26. 26.🌈 In the resistor colour code, which number does red stand for?
27. 27.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the colour of light (d) the length of a wire
28. 28.🔗 Series or parallel circuit: “one bulb out, all go out”? (a) parallel (b) series
29. 29.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a woollen thread. Does the bulb glow? (a) No (b) Yes
30. 30.⚠️ Is it safe to poke things in a socket? (a) safe (b) not safe
31. 31.🔌 Is a speaker an input or an output for a microcontroller? (a) input (b) output
32. 32.🤖 if (light < 400 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 580 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
33. 33.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
34. 34.What does a push button do? (a) flips up or down (b) closes when tipped over (c) springs back when let go (d) closes near a magnet
35. 35.🌈 A resistor has the colour bands green, violet, black. What is its value (in ohms)?
36. 36.⚠️ About how many volts do home sockets in India supply? (a) 1.5 V (b) 9 V (c) 230 V (d) 12 V
37. 37.⚠️ Is it safe to dry your hands first? (a) safe (b) not safe
38. 38.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a rubber eraser across the gap. Does the bulb glow? (a) Yes (b) No
39. 39.Which of these is an input? (a) a keypad (b) a motor (c) an LED (d) a speaker
40. 40.Which of these is true of a series circuit? (a) each gets the full volts (b) own switch for each bulb (c) bulbs share the voltage (d) many paths for current

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